U.S. Pat. No. 5,163,472 issued Aug. 11, 1992 to Farnworth et al. discloses an immersion suit having a particular collar structure formed by a band of compressible material encircling the neck of the wearer and forming a seal there around by tightening of a strap around the outside circumference of the collar to force the compressible material toward the neck of the wearer and form the seal.
In this suit, the collar is split, i.e. opens as does the front of the immersion suit by means of a reclosable fastener and provides a waterproof seal when closed. This structure has been proven satisfactory in use, however, it requires the presence of an outside strap and buckle and the threading of the strap through the buckle before a seal around the neck could be produced. Thus, where the suit was being worn open for comfort and if an emergency arises it may be necessary to rapidly and/or under adverse conditions close the front of the suit and then tighten the outside strap against the buckle to obtain the required protection. This is time consuming and in some cases, awkward, since the buckle is located under chin out of the view of the user. The tension applied around the neck need not be uniform which may lead so some discomfort to the user and an imperfect seal.